The invention relates generally to a method of processing a multilayer film and more particularly to a method of processing a multilayer film with a barrier layer and forming a reaction layer for plugging openings in the barrier layer.
Generally, a multilayer film having a barrier layer is used in variety of applications. Non-limiting examples of a device using a multilayer film with a barrier layer are food packages and bottles having barrier foils used to keep food fresh by keeping gases such as oxygen, humidity, or carbon dioxide in or out. Other example of a device using multilayer film is an electroluminescent (EL) device known in the graphic display and imaging art. Such multilayer film barriers are the object of increasing interest in the packaging, pharmaceutical, optical and electronic industries, and have to be employed when the need for flexibility, optical transparency, weight or cost rules out the use of truly impermeable substrates such as metal foils or glass sheets. The multilayer film usually includes a substrate layer along with the barrier layer for impeding the permeation of moisture, oxygen, carbon dioxide and other permeants. However, the presence of defects such as pores, pinholes, cracks or other imperfections in the barrier layer limits the performance of the multilayer films, thereby, making the multilayer films pervious to environmental factors such as oxygen, water vapor, carbon dioxide, hydrogen sulfide, SOx, NOx, solvents, and the like. The environmental factors, typically oxygen and water vapor permeation, may cause degradation over time and thus may decrease the lifetime of the electroluminescent devices in flexible applications. Advanced barrier films which can limit permeation to acceptably low levels exist but typically require multiple fabrication steps and hence are time consuming and uneconomical. Moreover, even these advanced barriers are still limited by pinholes and only barely meet the requirements in terms of average permeation and observed pinhole density.
Therefore, there is a need to improve the performance of the multilayer film and to develop a method of doing the same, in a manner requiring a minimal number of processing steps.